Position sensitive illumination system

ABSTRACT

A position sensitive illumination system for a patient includes an illumination source and at least one sensor structured and configured to selectively activate the illumination source in dependence of movement of the patient. Illumination source and/or sensor may be provided to one or more portions of a patient interface, e.g., a mask assembly, to thereby allow automatic activation of the illumination source when the patient moves to a predetermined position. Illumination source provides a directed lighted path for the patient as the patient moves about, e.g., during nocturnal visits to the bathroom, thereby avoiding the awakening of a bed partner.

CROSS REFERENCE TO APPLICATION

This national phase application claims the benefit of PCT ApplicationNo. PCT/AU2005/000704, filed May 16, 2005, which claims the benefit ofU.S. Provisional Application No. 60/571,487, filed May 17, 2004, each ofwhich is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This application is directed to a position sensitive illuminationsystem.

2. Description of Related Art

Typical patients with sleeping disorders, such as obstructive sleepapnea (OSA), and even people (also referred to herein as “patients”)without sleep breathing or other disorders can remain in an awake statelying in bed prior to going to sleep. Some patients may prefer to read abook or relax before going to sleep.

The bedroom environment at night and during sleep is typically poorlylit or not illuminated at all. The patient may therefore use a roomlight or switch on a bedside lamp to read. Bedside lamps typically throwstray light in most directions and may disturb a sleeping bed partner.

Another problem is that occasionally patients at night find need to getup and visit the bathroom or kitchen, or the need to otherwise arise.Typically, such a patient will switch on a light by fumbling in the darkfor a light switch or search for a nearby flashlight.

A patient's travel or walking path during such visits should preferablybe lit, therefore either room lighting or a flashlight is required, thelatter to prevent disturbing a bed partner.

Some patients may also use a light-activated lamp or “night light” thatplugs into a general purpose power outlet in the home. The lampilluminates a space in the adjacent vicinity when ambient light levelsfall. The space remains illuminated whether the patient or bed partneris awake or asleep. This stray light can disturb patients and bedpartners when they wish to sleep. They also illuminate only a definedspace, rather than the intended path of movement for a patient, e.g.,the path from the bed to the bathroom.

Further, switching on of room lights can have a negative effect oncircadian rhythms. Strong illumination especially reflected into theeyes is known to wake up patients, e.g., to a level of alertness thatmay diminish their ability to fall asleep again.

Therefore, a need has arisen to develop a system to allow for convenientand automated lighting of a patient's intended path, while preferablyproviding minimal disturbance to a patient and the patient's bedpartner.

SUMMARY OF THE INVENTION

One aspect of the invention aims to ameliorate one or more of the abovenoted problems.

Another aspect is directed to an illumination system that switchesitself on when the patient assumes a predetermined position, e.g.,either mobile or sitting up erect in bed, and switches off during sleep,e.g., when the patient is lying down.

Still another aspect is to provide a system in which a patient waking atnight is not overly awakened so that the patient may fall asleep againmore easily without trouble.

Another aspect of the invention is directed to a switching circuit thatmay prevent inadvertent switching on in certain and/or common sleepingpositions, e.g., laying on a side in an oblique manner or lateral bodyposition.

The position sensitive illumination system may be applied in a number ofways, including but not limited to a system that is integrated into ahuman interface such as a breathing mask system, an accessory that canbe attached to an interface, or a stand-alone product that can be usedin conjunction with a multitude of therapy equipment or additionallighting as required.

The systems described herein may also be used during non-therapy relatedsessions, for example, simply reading in bed during the night.

These and other aspects of the invention will be described in orapparent from the following detailed description of preferredembodiments.

BRIEF DESCRIPTION OF DRAWINGS

Preferred embodiments of the invention will be described in relation tothe following drawings, in which:

FIG. 1 is a perspective view of a position sensitive illumination systemaccording to a first embodiment of the present invention in which amodel patient's head is upstanding and light is generated;

FIG. 2 is a perspective view of the system shown in FIG. 1, in which themodel patient is lying asleep on his side and light is not generated;

FIGS. 3 and 4 are partial schematic side views illustrating basesupports according to embodiments of the present invention;

FIG. 5 is a perspective view of a position sensitive illumination systemaccording to another embodiment of the present invention, with theillumination source shown in exploded view for clarity;

FIGS. 5A and 5B are schematic views showing exemplary positioning anglesof sensors according to an embodiment of the present invention;

FIG. 6 illustrates a schematic diagram of a blower according to yetanother embodiment of the present invention; and

FIG. 7 illustrates a schematic block diagram of a position illuminationsystem along with possible options for upgrading the basic systemaccording to yet another embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate a mask system integrated with a positionsensitive illumination system according to an embodiment of the presentinvention.

As shown in FIGS. 1 and 2, a model patient 10 is provided with a patientinterface, e.g., mask assembly 20, which in this embodiment is a fullface mask, although other mask assemblies, e.g., nasal masks, prongs,nozzles, and even nasal cannulae, etc., are contemplated as well.Various components of mask assembly 20 are commercially available fromResMed Limited and are described in U.S. pat. No. 7,406,965,incorporated herein by reference in its entirety.

Mask assembly 20 includes in this example headgear including upper andlower straps 25, 30 that are provided to a mask 35. A cushion 40 isprovided to mask 35. Typically, although not necessarily, mask 35 is inthe form of a rigid polycarbonate shell, while cushion 40 is in the formof a flexible, elastic and/or silicone based sealing member that isstructured to comfortably contact the patient's face without localizedpressure points. Mask 35 is provided with a swivel elbow 45 which isconnectible to an air delivery tube 46 (shown in a disconnectedposition), which is in turn supplied with pressurized breathable gasfrom a blower or flow generator (not shown). Mask 35 typically includesone or more ports 48 that are provided for pressure monitoring, or forthe supply of supplemental gas, such as oxygen, etc. Ports 48 aretypically provided with caps when not in use.

Mask includes an extension or joining member 50 that is structured tosupport a forehead support 55 having forehead pads 55.1. Upper strap 25is connected to forehead support 55 via a releasable clip connector 60.Similarly, lower strap 30 is provided to mask 35 via releasable clipconnector 60.

Position Sensitive Illumination Assembly

Mask assembly 20 includes and/or is provided with a position sensitiveillumination assembly 65, as shown in FIG. 1. In one basic form,assembly 65 includes an illumination source 70 and at least one sensor75, preferably non-Mercury tilt switches, although it is also possibleto use Mercury switches as well. In the embodiment of FIGS. 1 and 2, twosensors 75 are provided. At least one of the source 70 and sensor 75, ora component or combination of components thereof, is connected orotherwise provided to the patient interface, e.g., one or more portionsof mask assembly 20.

Preferably, at least a portion of illumination assembly 65 is formed asan integrated component of mask assembly. However, portions ofillumination assembly 65 could be retro-fitted to mask assembly 20, inwhich case the mask assembly would not need to be specifically designedto accommodate illumination assembly 65.

In either case, structure will be provided to support the selectedportions of assembly 65 on the patient interface. That structure, e.g.,as shown in FIG. 3, may include at least one base support 76 having afirst portion 77 provided to the patient interface, e.g., at theintersection of T-shaped cross-bar of forehead support 55, and a secondportion 78 that is provided to support source 70 and/or sensor 75.Sensor 75 is not shown in FIG. 3, for clarity purposes, but is connectedto one or more of wire ends 79 a, 79 b of source 70. Positioning in thismanner is advantageous because support 76 is located between the twoforehead support pads 55.1 shown in FIGS. 1 and 2. Because the pads 55.1are generally spaced away or offset from the forehead support 55, thereis ample room for the support 76 and little possibility that the support76 can contact the patient's forehead. One such pad 55.1 isschematically shown in phantom in FIG. 3 to illustrate this offset.

In general, components of the illumination assembly 65 should bepositioned on the interface in such a way as to avoid interference withthe patient, e.g., the patient's line of vision, etc. In addition, thecomponents should be placed such that they maintain a low profile, so asto avoid snagging and interference with head movement. Further, at leastthe source 70 should be positioned such that it best illuminates thepatient's path during movement. Positioning of the source 70 on theforehead support 55 achieves this goal, although there are otherpositions which would be acceptable.

Second portion 78 may be in the form of a fixture, e.g., a ball socket,which is adapted such that that source and/or sensors can be selectivelyattached and/or removed. Of course, multiple supports may be provided tosupport separate components of illumination assembly.

As shown in FIG. 3, support 76 includes front and rear walls 81, 82 oneither side of forehead support 55. As mentioned above, rear wall 82would not contact the patient's forehead, because forehead support pads55.1 space the forehead support 55 away from the patient's forehead. Inthis embodiment, support 76 may act as a clip so that it can beselectively attached to and detached from the forehead support 55. Frontand rear walls 81 and 82 may be pre-tensioned or provided with a springso as to be biased towards one another, to grasp support 55. Fingerengagement portions 84 may be provided to facilitate operation.

In addition and/or in the alternative, one or more screws (not shown) orother fastening devices may be provided to connect support base 76 tomask assembly, e.g., forehead support 55.

Support 76 may be connected to patient interface in a number ofdifferent ways. For example, as shown in FIG. 4, first portion 77,instead of being separate, may be provided in one piece with maskassembly 20, e.g., cross-bar of support 55. Second portion 78 may alsobe formed in one piece with support 55. It is contemplated that maskassembly could be sold to customers with a standard forehead support,without illumination assembly. An upgrade kit could be sold which wouldinclude sensor/source and a forehead support specifically adapted tosupport an illumination assembly, e.g., source and/or sensor.

The illumination source 70 is preferably mounted to a flexible and/oradjustable positioning joint, such as gimbals or ball joint 85. Gimbal85 or another universal joint allows the user to variably adjust thedirection of illumination according to the relative positioning of thepatient. The light could, for example, provide an ideal position forreading a book whilst sitting up in bed or an appropriate angle to allowthe patient to light their intended path for a nocturnal visit to thebathroom. Universal joint may either lock manually in position, befriction locked whereby a overriding force is applied to adjust positionand release to lock, or may otherwise be automated into a position.Sensor 75 is preferably not adjustable, at least once the patientinterface is donned by the patient. Sensors can be attached bymechanical fastening and/or adhesives, e.g., self adhesive tape.Further, sensors may be mounted in an adjustable fashion to fine tuneand/or adjust their on/off angle/threshold.

As shown in FIG. 1, illumination source 70 is on, meaning that light isprovided. In addition, the light generally follows the walking path ofthe patient, since the light is mounted on mask 35 in a way that followsthe movement of the patient's head. FIG. 2 shows the patient 10 in asleep mode, in which the head is resting on its side against a pillow80. In this position, the sensor 75 is in the position which causes theillumination source 70 to be deactivated.

As shown in FIGS. 1-4, illumination source 70 and/or sensors 75 areprovided on the forehead support 55. However, either one or both ofthese elements may be provided on other parts of the mask assembly 20,such as the mask 35, straps 25 or 30, elbow 45, ports 48, etc. In otherembodiments, e.g., source 70 may be provided to mask 35, sensor may beprovided on forehead support 55, and a power source may be provided onheadgear straps. Moreover, the embodiments of FIGS. 1-4 is integratedinto a mask assembly to minimize size, weight, components, andobtrusiveness to a patient.

Illumination Source

Illumination source 70 may include, but is not limited to, one or moreincandescent lamps, cold-cathode fluorescent lights, fiber optic lights,light emitting diodes (LEDs), Xenon high intensity lamps, and/or halogenlamps, etc.

LEDs are long lasting, inexpensive, and tend to throw softer light thatis easier on the eyes (less strain) compared with other types of lights,such as halogen lights. LED illumination also offers various brightnessincluding ultra bright versions that offer high illumination howeverwith desirably low power consumption. Low power consumption results in asmaller battery storage device that results in smaller size and lessweight therefore increased comfort to the patient. One or more LEDs maybe used depending on the illumination and intensity required.

LEDs may be mounted together or apart in different areas of theinterface system. For example, the LEDs may be mounted into headgearstrap on either side of the head. In another example, only a single LEDis used.

Preferably, a reflector 71 is provided to back the illumination source,e.g., one or more LEDs, to thereby provide a greater concentration oflight towards the required area to be illuminated. The reflector alsoserves to prevent stray light and minimize intensity of lamp required.The ideal illumination provides concentration towards the center of thelight beam and gradually softens towards the edge that may be achievedby diffusing more light near the reflector edge. Reflector shouldeffectively lower the power requirements for the power source.

In addition, shield members 72 may be provided in conjunction with theillumination source and/or reflector to direct a more focused beam oflight, to thereby illuminate the patient's path and to help preventwaking of the patient's bed partner. Shield members can mask the lightfrom certain zones to provide a defined illumination zone. Shieldmembers can take the form of a hood, e.g., having the shape of a trafficlight hood, or a blinder, such as a horse blinder.

The emitted light may also be provided with a filter or otherwisefiltered to allow certain objects to be more readily seen in darksurroundings. For example, a red filter may be used to preserve nightvision without straining the eyes.

Sensor

As described above, sensors may take the form of Mercury switches ornon-Mercury switches. However, sensor can be any type of tilt or motionsensor, for example yaw/roll sensors such as used in automotive chassisstability systems. While the illustrated embodiments make use of twosensors, the use of a single sensor or more than two sensors is alsocontemplated.

Mercury tilt switches (usually found in home security systems thatincorporate a capsule of Mercury) are electrically communicated viawired or wireless connection in series to illumination source. Tiltswitches when positioned according to the patient supine sleepingposition provide no illumination because both tilt switches are angledin the off position with the open circuit ends pointing towards thecenterline of the patient. The orientation of the sensors depends inpart on the patient's sleeping position. Ideally, the orientation isadjustable by the patient, since patients may sleep in differentpositions due to, e.g., higher pillows. As shown in FIGS. 5A and 5B, theangle a from the front may be in the range of about 50°-90°, and theangle β from the side may be in the range of about 25°-40°, althoughother angles (higher or lower) are possible. See, e.g., FIGS. 1, 2 and5. Should a patient roll onto their side (oblique or lateral position),the lower tilt switch can close, however the uppermost switch remainsopen.

Therefore the positioning of sensors help prevent inadvertentillumination in these general body positions as the sensors are wired inseries and the lamp will not illuminate unless both tilt switches areclosed (connected). Logic with the sensor(s), and/or in the air deliverydevice, prevents or minimizes inadvertent illumination in certain bodypositions. For example, it is preferable that the illumination source 70does not operate in any typical sleeping position lying down, i.e.,supine (on back), prone (on front), lateral (on side), and oblique (onside facing toward bed). As the prone position is uncommon during theuse of sleep therapy equipment such as masks, the position sensor maynot accommodate this position. Therefore, sensors should be arrangedsuch that at least one is open in at least the above body positions, sothat source 70 does not provide illumination. As a patient sits orstands upright, the sensor or sensor array closes the electric circuitand the lamp illuminates.

Non-Mercury tilt switches are preferred for patient safety, since theydo not include Mercury which may be a health hazard. Non-Mercury tiltswitches typically include a conductive ball, bead or pill inside asmall canister, track or guide with the circuit contacts at one end.Tilting the switch one way opens the circuit While tilting the oppositedirection closes the switch.

If provided on the patient interface, sensor 75, e.g., tilt switches,may include anti-vibration structure to damp vibration as the user walksto prevent or minimize the lamp flickering due to switches opening andclosing repeatedly. Such structure may take the form of a dampingelement built into sensor, to dampen the body of sensor, or otherwisedamp assembly 65. This damping, in one example, may be achieved bymounting the tilt switch to the assembly via a soft visco-elasticmaterial such as very soft silicone.

Power Source

Illumination assembly 65 includes or is provided with a power source forproviding power to the illumination source and/or the sensor. Powersource may take the form of a battery, either of the rechargeable or thenon-rechargeable type. The battery may be held on the positionillumination system via a battery holder, which in embodiments may beprovided as part of the mask assembly 20, illumination assembly 65,and/or support 76. For example, one or more batteries 73 (FIG. 4) may beprovided within the same casing that holds the illumination source. Inanother embodiment, as seen schematically in FIG. 1, battery 91 may beprovided to one or more of headgear straps 25, 30. Batteries 91 mayinclude backing including a hook-type fastener which cooperates with theloop material on the straps 25, 30. The batteries 91 may be connected tosource 70 by wires 93 that are routed directly to source 70 or along theheadgear straps 25, 30 and other components of the mask assembly. Forexample, clips 60 could include electrical contacts which complete acircuit when the clips 60 are attached to the forehead support 55.Batteries 91 are shown to be positioned within a recess of adoubled-over portion of straps 25, 30.

A rechargeable version may utilize wired or wireless chargingtechnologies, such as that used in rechargeable toothbrushes.Rechargeable versions may offer user convenience in not having toreplace batteries often especially for frequent users. Compact buthigh-power storage is preferred, for example Lithium-Ion or Nickel MetalHydride batteries used in small mobile cell phones.

Preferred battery storage device that requires no additional wiringharness from the patient to a power source not located adjacent to thebody. The battery storage device is preferably compact, such as alkaline‘coin’ batteries that may be stacked to achieve higher storage capacityof voltages to offer the required illumination life before batteries runflat on power.

A solar charging version allows the battery storage medium to be chargedduring day, with enough power stored for subsequent use during thenight.

Stand Alone Position Sensitive Illumination

FIG. 5 illustrates yet another embodiment of the invention. A positionsensitive illumination assembly 100 is provided to a model patient'shead 105. Assembly 100 includes a patient interface, e.g., a head strap110, one or more sensors, e.g., switches 115, and an illumination source117 (shown as exploded view; connectable to wire ends 120 and 125).Source and sensors may be as described above. In this embodiment,assembly 100 is provided to a patient who is not using a mask for sleeptherapy, i.e., a stand alone assembly which in fact need not include asensor in a more basic form. In one embodiment, it may be possible toprovide an override switch to deactivate the sensor, in the event thepatient is taking a break from therapy. The override switch can beformed as part of the illumination assembly, or as part of a blower orflow generator.

Headgear 110 includes in this example a first strap 111 guided along thepatient's forehead and toward the back of the head along the temples ofthe patient. A second strap 112 is provided over the top of thepatient's head. A support 113 is provided with first and secondconnection portions, e.g., slotted connectors, for the ends of firststrap 111, and a third connection portion for second strap 112. Support113 includes provision for the support of sensors 115, as well asillumination source 70. For example, support may include receivingstructure which allows source and/or sensors to be automaticallysnap-fitted into place or fastened in any suitable manner. In anotherembodiment, sensors can be attached to a bracket with self-adhesivetape. In still another embodiment, sensor, source and/or mounts may becoupled using hook and loop fasteners. Preferably, support 113 includesa padded layer in contact with the patient's head.

Integration with Flow Generator

As shown in FIG. 6, power to sensor(s) and/or illumination source mayalso be provided via air flow generator 200, which is typically pluggedinto an outlet in the patient's room and is described, e.g., in relationto U.S. Pat. No. 6,591,834, incorporated herein by reference in itsentirety. Air flow generator 200 could include an additional wire orelectric cable 202 that may be routed along or through or otherwiseintegrated into air delivery tube 6 for connection to illuminationsource and/or sensor.

A wire or cable may also run to an alternate battery source, forexample, mounted to a belt or some portion of the patient's body. Thewire/cable may also run to an alternate power source such the homegeneral power point.

In FIG. 6, illumination source may be connected to or otherwise providedto a hole formed in an elastomeric vent insert 204 which can beselectively attached to and removed from the mask assembly, which inthis case is a nasal mask assembly 206. The insert 204 is normallyprovided with a plurality of holes 207, one of which can be used tosupport the illumination source 70, provided the remaining holesprovided ample gas washout. Otherwise, an additional hole can be added,or the insert 204 can be replaced with a new insert having the propernumber of holes, one of which is for source support and the others ofwhich are for gas washout. The elastomeric nature of the insert canfrictionally hold the source 70 in the desired position. The source maymove in one or more planes, e.g., via a flexible joint, or a hinge orball joint, to direct the light beam in the intended direction.Otherwise, the source may be provided directly within the shell of maskassembly 206.

In another embodiment, one or more illumination sources may be supportedby ports 48, as shown in FIGS. 1-2, following temporary removal of portcaps. In one form, source may be mounted on a stem which is frictionallyreceived within port 48. Source could include a battery and an on/offswitch, without the need for a sensor. Preferably, the source wouldallow for some form of adjustability, e.g., via a ball joint or aflexible, deformable stem.

Signals produced by sensor(s) may be communicated by wire or wirelessmethods to flow generator 200, or another diagnostic device. Forexample, flow generator includes a sensor module 208 that provides asignal to controller 210 to switch off impeller 212 when patient sitsup, or to stop the flow of air to mask, based on output from sensor, andpreferably before mask is taken off face to prevent blow out and noisethat may disturb a bed partner. In this embodiment, mask may notnecessarily include an illumination source and/or position sensor, eachof which may be provided elsewhere in the patient's room. Suchinformation may also be used in diagnostics to determine and record headand/or body position related to severity of OSA.

As shown in FIG. 6, a light sensor 300 built into flow generator 200 cansense when a patient aims the activated illumination source towards andit can also conveniently turn the machine on and off. The sensor shouldpreferably be able to differentiate ambient lighting from lightgenerated by illumination source, which may be achieved by providing thesource with a filter and adjusting the sensor to such filtered sourcelight. This provides a ‘touchless’ start and stop function of thetreatment device, e.g., flow generator. Further, machine performance maybe modified relative to the sensed body position of the patient.

Additional Embodiments

FIG. 7 illustrates position illumination system in a basic form,including illumination source 70 and sensor 75. A channel 90 is providedto allow communication between illumination source and sensor. Channelmay be mechanical, magnetic and/or electrical, etc. in nature. Moreover,wired and/or wireless communication channels may be provided.

FIG. 7 includes a bank 95 of optional subcomponents which are describedbelow. One or more subcomponents of bank 95 may be provided directly toor integrated into flow generator and/or illumination system, e.g., aprinted circuit board including the required circuitry and/or logiccomponents.

Sensor is optionally in communication with a sensitivity module 700 thathas an ability to adjust the sensitivity of angular adjustment of thesensors so that in certain body positions, the patient may not wish thelamp to illuminate as readily.

An “on/off” switch 702 may be provided to override the position sensorin case the device is being transported and not being used. Switch 702may also have an option whereby an additional light sensor completelyopens the circuit during daylight ambient light levels.

Selectable brightness switch 704 may be provided so a patient can selectmore than one illumination level. These may be defined steps orotherwise fully variable. The light intensity may also automate toadjust beam intensity according to ambient room lighting levels, e.g.,by use of a photo resistor. A lower intensity may be preferred duringreading where the area to be illuminated is in close proximity to theface as opposed to a path where the patient is walking.

A soft-start illumination module 706 may be provided to minimizeeyestrain similar to that used in automobile delay courtesy lightsystems. When the device is switched on as a patient becomes upright,the source 70 slowly illuminates (by steps or continuously variable) tothe defined intensity to prevent sudden eyestrain and/or to avoiddisruption of the patient's or bed partner's circadian rhythms. This maybe done using several methods including use of capacitors or simpleelectronic dimming circuit. For example, the ramping and/or stepping ofthe light brightness/intensity occurs over about 2-10 seconds,preferably about 5 seconds.

This above feature is most useful where a patient has been sleeping andis awakened with the desire to visit the bathroom or kitchen at night.The patient's eyes have acclimatized to darkness and therefore asoft-start feature provides substantially improved patient comfort. Theother benefit prevents the patient from being harshly affected, whichmay reduce the ability for a patient to fall asleep again on return tobed.

An indicator 708, such as a small LED, can be used to signal low batterypower to notify a user to replace and/or recharge the battery storagedevice. Additional options or features may be provided in module 710.

Patients with a physical disability may also benefit from aspects of theinvention, e.g. loss of an upper limb or arthritis, as two examples. Inone example of an application, the position sensitive components (e.g.,sensors) may be mounted to the patient's head, and a bedside light orseries of lights may be connected.

In another alternative, the sensor may be a pressure detector which isprovided in the patient's pillow, bed sheets, mattress, etc. The sensormay be in the form of a pressure sensitive mat or floor piece providednext to the patient's bed. Sensor may be provided to a patient's walkerand trigger activation of illumination source when the walker is moved.

Sensor may be in the form of a magnetic circuit. For example, apatient's eyeglasses can be provided with a magnetic component, which,when the patient dons the glasses, cooperates with a complementarymagnetic component supported by the patient interface, e.g., mask, tothereby complete an electric circuit and thereby activate theillumination source, which may be provided on glasses or mask. When thepatient removes the glasses, e.g., when a reading session is completeand the patient desires sleep, the glasses are removed and theillumination source goes out. When the patient wakes at night to visitthe bathroom, the glasses are donned, thus activating illuminationsource.

Alternatively, the illumination source may be provided to the patientinterface, and the position sensitive components (e.g., a motiondetector) may be provided to the patient's surroundings in the room.

In other embodiments, both the sensor and illumination source may beprovided somewhere in the patient's surroundings rather than beingsupported on the patient.

Embodiments of the invention may include integral components in a singleassembly or module, or a number of parts can plug into each other, e.g.,a reflector, battery, switch, position sensor, etc. In still furtherembodiments, structure may be provided to swap and change any of thecomponents as required by the patient.

For example, a general kit can be provided along with a number ofoptional lamp/reflectors to suit certain users or larger battery storagemediums for patients wishing to read for extended periods.

Furthermore, the use of position sensitive control is not limited withuse to an illumination source. For example, instead of or in addition toselectively (de)activating an illumination source (accessory) independence of a signal from one or more sensors, such control could beapplied to other accessories, e.g., stereo/radio and/or speakers, atelevision or other appliance, etc. Moreover, the position sensitivesensor can be used to produce a signal, e.g., an alarm, in the event thepatient, e.g., the patient's head, assumes a sleeping position when thepatient should be awake.

The invention has been described in reference to preferred embodimentsthereof, which are intended to be illustrative and not limiting. Variousmodifications and changes would be apparent to those of ordinary skillin the art without departing from the scope of the invention.

The invention claimed is:
 1. An air delivery system comprising: a flowgenerator; a patient interface coupled to the flow generator to receivepressurized gas via an air delivery conduit positioned between the flowgenerator and the patient interface; and a position sensitiveillumination system which is mounted on the patient interface, whereinthe position sensitive illumination system comprises an illuminationsource; at least one sensor that selectively activates the illuminationsource based on positioning of the patient in use; and a patientinterface that supports at least one of the illumination source and thesensor, wherein the at least one sensor activates the illuminationsource when the patient is in a sitting or standing upright position anddeactivates the illumination source when the patient is in a supine,prone, lateral or oblique position.
 2. An air delivery system accordingto claim 1, wherein the patient interface supports the illuminationsource and the at least one sensor.
 3. An air delivery system accordingto claim 1, wherein the patient interface includes a strap structuredfor support in use by the head of the patient.
 4. An air delivery systemaccording to claim 1, wherein the patient interface comprises a maskassembly.
 5. An air delivery system according to claim 4, wherein themask assembly includes a forehead support that supports at least one ofthe illumination source and the at least one sensor.
 6. An air deliverysystem according to claim 4, wherein the mask assembly includes aheadgear strap that supports at least one of the illumination source andthe at least one sensor.
 7. An air delivery system according to claim 6,wherein the headgear strap supports a battery for the illuminationsource, and the illumination source is provided to a forehead support ofthe mask assembly.
 8. An air delivery system according to claim 4,wherein the mask assembly includes an elbow that supports at least oneof the illumination source and the at least one sensor.
 9. An airdelivery system according to claim 4, wherein the mask assembly includesa port .
 10. An air delivery system according to claim 1, furthercomprising a base support configured to be provided to the patientinterface, the base support supporting at least one of the illuminationsource and the at least one sensor.
 11. An air delivery system accordingto claim 10, wherein the base support includes a first portion to beaffixed to a portion of the patient interface and a second portion tosupport the illumination source.
 12. An air delivery system according toclaim 10, wherein at least a portion of the base support is provided inone piece with the patient interface, which is a mask assembly.
 13. Anair delivery system according to claim 1, wherein the illuminationsource includes at least one of an LED, an incandescent light source,and a halogen bulb.
 14. An air delivery system according to claim 13,wherein the illumination source includes an array of LEDs.
 15. An airdelivery system according to claim 1, wherein the illumination sourceincludes a reflector.
 16. An air delivery system according to claim 15,wherein the illumination source further comprises a shield member. 17.An air delivery system according to claim 1, wherein the at least onesensor includes a Mercury switch.
 18. An air delivery system accordingto claim 1, wherein the at least one sensor includes a non-Mercuryswitch.
 19. An air delivery system according to claim 18, wherein twonon-Mercury switches are provided, each being oriented such that atleast one switch within a predetermined angular range is open in typicalsleeping positions of the patient.
 20. An air delivery system accordingto claim 1, wherein the at least one sensor includes a sensor arrayincluding at least two illumination sources.
 21. An air delivery systemaccording to claim 1, wherein the at least one sensor is provided to thepatient interface.
 22. An air delivery system according to claim 1,wherein the at least one sensor is not provided as part of the patientinterface.
 23. An air delivery system according to claim 22, wherein atleast a portion of the at least one sensor is provided to the patient'seye glasses.
 24. An air delivery system according to claim 22, whereinthe at least one sensor is provided as part of the patient's bed pillow,mattress, or other surroundings.
 25. An air delivery system according toclaim 1, further comprising a power source to power at least one of theillumination source and the at least one sensor.
 26. An air deliverysystem according to claim 25, wherein the power source is rechargeable.27. An air delivery system according to claim 1, the position sensitiveillumination system further comprising an override on/off switch.
 28. Anair delivery system according to claim 1, the position sensitiveillumination system further comprising a sensitivity module.
 29. An airdelivery system according to claim 28, wherein the sensitivity module isconfigured to gauge ambient light conditions in the patient's vicinity.30. An air delivery system according to claim 1, the position sensitiveillumination system further comprising a filter to filter light from theillumination source.
 31. An air delivery system according to claim 1,the position sensitive illumination system further comprising a dimmermodule adapted to adjust the brightness level of the illuminationsource.
 32. An air delivery system according to claim 1, the positionsensitive illumination system further comprising a soft start moduleconfigured to slowly ramp/step power to the illumination source from alower level to a predetermined higher level.
 33. An air delivery systemaccording to claim 32, wherein the ramping/stepping occurs over about2-10 seconds.
 34. An air delivery system according to claim 33, whereinthe ramping/stepping occurs over about 5 seconds.
 35. An air deliverysystem according to claim 1, further comprising at least one vibrationdamper provided to the patient interface.
 36. An air delivery systemaccording to claim 35, wherein the vibration damper is a silicone mountfor at least one of the illumination source and the at least one sensor.37. An air delivery system according to claim 1, further comprising abase support supporting the illumination source and the sensor, thesupport including at least one slotted connector for attachment of ahead strap.
 38. An air delivery system according to claim 1, furthercomprising circuitry to deactivate the flow generator in dependence ofoutput of the at least one sensor.
 39. An air delivery system accordingto claim 1, wherein the flow generator includes a light sensor adaptedto receive illumination from the illumination source, to selectivelyactivate and deactivate the flow generator.
 40. An air delivery systemaccording to claim 1, wherein at least a portion of the positionsensitive illumination system is powered via the flow generator.
 41. Aposition sensitive illumination system for a patient, comprising: apatient interface that engages the head of the patient in use, thepatient interface comprising a support that engages the forehead of thepatient in use; an illumination source supported by the patientinterface support; and a first tilt switch and a second tilt switchsupported by the support, wherein open circuit ends of the first tiltswitch and the second tilt switch point towards a centerline of thepatient in use and are provided at a first angle of about 50°-90° fromeach other, the first tilt switch and the second tilt switch are eachprovided at a second angle of about 25°-40° to vertical when the patientis in an upright position, and the first tilt switch and the second tiltswitch close a circuit connected to the illumination source when bothare in a closed position to illuminate the illumination source.
 42. Aposition sensitive illumination system according to claim 41, whereinthe first tilt switch and the second tilt switch are in series.
 43. Aposition sensitive illumination system according to claim 41, whereinthe first angle and/or the second angle of the first tilt switch and/orthe second tilt switch is adjustable.
 44. A position sensitiveillumination system according to claim 1, wherein the first tilt switchand the second tilt switch each comprise Mercury tilt switches.
 45. Aposition sensitive illumination system according to claim 41, whereinthe first tilt switch and the second tilt switch each comprise aconductive element and circuit contacts.
 46. A position sensitiveillumination system according to claim 45, wherein the conductiveelement comprises a ball, bead, or pill.
 47. A position sensitiveillumination system according to claim 45, wherein the circuit contactsare provided in a canister, track, or guide.
 48. A position sensitiveillumination system according to claim 41, wherein the patient interfacecomprises a mask assembly.
 49. A position sensitive illumination systemaccording to claim 48, wherein the support comprises a forehead supportcomprising at least one forehead pad.
 50. A position sensitiveillumination system according to claim 41, wherein the illuminationsource is adjustably supported by the support.
 51. A position sensitiveillumination system according to claim 50, wherein the illuminationsource is supported by a gimbal, a ball joint, or a universal joint. 52.An air delivery system comprising: a flow generator; a patient interfacecoupled to the flow generator to receive pressurized gas via an airdelivery conduit positioned between the flow generator and the patientinterface; and a position sensitive illumination system which is mountedon the patient interface, wherein the position sensitive illuminationsystem comprises an illumination source; a first tilt switch and asecond tilt switch supported by the support, wherein open circuit endsof the first tilt switch and the second tilt switch point towards acenterline of the patient in use and are provided at a first angle ofabout 50°-90° from each other, the first tilt switch and the second tiltswitch are each provided at a second angle of about 25°-40° to verticalwhen the patient is in an upright position, and the first tilt switchand the second tilt switch close a circuit connected to the illuminationsource when both are in a closed position to illuminate the illuminationsource.